I've got an app coming out of beta that runs web accessibility scans, which uses Elixir+Ash. Beta testers loved it, it's been very stable and I barely had to touch it over the beta period.
This app has a lot of complex headless browser flows that rely a lot on Ash.StateMachine, and Ash has only gotten better the deeper I've gotten into it. The app gets more simple and stable the more I integrate with Ash.
The declarative "data-oriented programming" paradigm took some getting used to (I come from PHP) but it makes so much sense and makes it easy to plug Ash resources into any other use case. Deriving a JSON api is an easy example.
In another app I'm using Ash.Reactor to model agentic AI workflows (it's just RAG but with extra steps). Reactor was originally intended as a saga orchestrator that models workflows as a DAG. DAG is the perfect abstraction for this use case and it works ridiculously well.